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[-next] rtlwifi: kfree entry until after entry->bssid has been accessed

Message ID 20170630100843.9188-1-colin.king@canonical.com (mailing list archive)
State Accepted
Commit d0116f6f7b306bc2d1bfc98d7c7c80fe5f468c20
Delegated to: Kalle Valo
Headers show

Commit Message

Colin King June 30, 2017, 10:08 a.m. UTC 
From: Colin Ian King <colin.king@canonical.com>

The current code kfree's entry and then dereferences it by accessing
entry->bssid.  Avoid the dereference-after-free by moving the kfree
after the access to entry->bssid.

Detected by CoverityScan, CID#1448600 ("Read from pointer after free")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/wireless/realtek/rtlwifi/base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kalle Valo July 27, 2017, 10:58 a.m. UTC | #1 
Colin Ian King <colin.king@canonical.com> wrote:

> From: Colin Ian King <colin.king@canonical.com>
> 
> The current code kfree's entry and then dereferences it by accessing
> entry->bssid.  Avoid the dereference-after-free by moving the kfree
> after the access to entry->bssid.
> 
> Detected by CoverityScan, CID#1448600 ("Read from pointer after free")
> 
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Patch applied to wireless-drivers-next.git, thanks.

d0116f6f7b30 rtlwifi: kfree entry until after entry->bssid has been accessed
diff mbox

Patch

diff --git a/drivers/net/wireless/realtek/rtlwifi/base.c b/drivers/net/wireless/realtek/rtlwifi/base.c
index e36ee592c660..208f56297a75 100644
--- a/drivers/net/wireless/realtek/rtlwifi/base.c
+++ b/drivers/net/wireless/realtek/rtlwifi/base.c
@@ -1735,12 +1735,12 @@  void rtl_scan_list_expire(struct ieee80211_hw *hw)
 			continue;
 
 		list_del(&entry->list);
-		kfree(entry);
 		rtlpriv->scan_list.num--;
 
 		RT_TRACE(rtlpriv, COMP_SCAN, DBG_LOUD,
 			 "BSSID=%pM is expire in scan list (total=%d)\n",
 			 entry->bssid, rtlpriv->scan_list.num);
+		kfree(entry);
 	}
 
 	spin_unlock_irqrestore(&rtlpriv->locks.scan_list_lock, flags);